Either one should be fine and while probably not a good as an in tank swirlerizer, I've been happy with the Camco for the last 3 years. You wont find the spray action does a whole lot, but the key is being able to shut the valve and back fill the black tank, just make sure you don't OVERFILL!
Once you have it full-ish, pull the valve and watch how much more "stuff" comes out from the second or third dump. Yes, you could bring a hose through the trailer and stick it down the commode to do the same, but these are far easier IMO.